Jones



(No Model.)

- W. JONES.

VARIABLE CAM.

No. 284,860. Patented Sept. 11, 1883.

. is formed on the UNITED Sarss PAT NT @rrrca.

WVASHINGTON JONES, OF PHILADELPHIA, PENNSYLVANIA.

VARIABLE CAM.

SPECIFICATION forming part of Letters Patent No. 284,860, dated September 11, 1883. Application filed July 1-2, 1883. (No model.)

To all whom it may concern:

Be it known that I, WVAsHING'ro J ONES, a citizen of the United States, and a resident of Philadelphia, Pennsylvania, have invented certain Improvements in Variable Gains, of which the following is a specification.

My invention consists of a cam constructed and combined with mechanism, substantially as described hereinafter, so that the circumferential extent of the swell ofthc cam may be varied at pleasure.

In the accompanying drawings, Figure 1 is a side View of avariable cam made in accordance with my invention; Fig. 2, an edge view, Fig. 3, a section on the line 1 2, Fig. 1; and Figs. 4 and 5, perspective views of the two portions of the cam.

The cam is composed of the two plates A and B, the plate A being secured to the shaft G,inthe present instance byaset-screw, a, passing through the hub of the plate, and the plate 13 being circumferentially adjustable on the shaft and maintained in contact with the plate A by a collar, 1), on the said shaft. The proj ecting portion 10 of the cam between the points so and y, this portion being sometimes termed the swell of the cam, is partly on the plate A and partly on the plate B 5 and the object of my invention is to increase or diminish the circumferential extent of this swell by the adjustment of one of the plates so that the cam may have a longer or shorter dwell on the roller 1) or other object which the cam has to actuate.

It will be seen on reference to Fig. 5 that a portion of the plate A is cut away, so as to leave two abrupt shoulders, m n between which a toothed segment, (I, concentric with the shaft, plate. On the other plate, 13, is aproj ection, e, in whichare bearings for a small spindle, f, carryinga worm, M, which gears into the teeth of the segment d of the plate. \Vhen the worm is turned in one direction, the swell w of the cam will be diminished circumferentially in extent, and it will be increased in extent when the worm is turned in a contrary direction. The spindlef carries aworm-wheel, g, into which gears a worm, h, 011 a spindle, 1', having its bearing in the plate 13, the outer end of this spindle being preferably furnished with a star-wheel, j, the turning of which will necessarily result either in the circumferential con portion of the plate B where the projection c occurs, and the thickness of which (also shown in Fig. 2) is the same as that of the last-named portion, and partly of the thin portion of the plate 13, which always forms a bridge between the thick portion of the swell 011 the plate A and the thick portion of the swell on the plate B. In other words, the swell of the cam has the same continuity as asolid cam of uniform thickness. It will be understood, however, that to insurea proper continuity the roller 12, or other object against which the cam has to act, must be as wide as the thickest part of the swell of the cam.

\Vhile devices other than the system of worms and worm-wheels might be employed to adjust the plate B, these appliances are preferred, as they not only serve as mediums for adjustment, but also as locking devices for retaining the plate B of the cam in the position to which it has been adjusted. The adj ustment, moreover, can be effected while the can; is in motion by simply applying a suitable instrument to the star-wheel.

The cam is especially applicable to steamengines as a cut-off cam. XV, for instance, may be the valve-lifting rod of a steam-engine, the said rod carrying at its lower end the abovemcntioned roller 1) but the cam may also be used in many other connections, wherever a change in the duration of its dwell is desirable.

I claim as my invention A cam composed of two plates, one cireumferentially adjustable in respect to the other, in combination with mechanism, substantially as described, for effecting this adj ustment, and thereby increasing or diminishing the circumferential extent of the swell of the cam.

2. The combination of the two plates A and B 01' the cam, with a toethed segment on one In testimony whereoiihave signed mynz'unc plate and a spindle carrying aworm-wheel on to this specification in the presence of two sub- IO the other plate, substantially as set forth. scribing witnesses.

3. The combination of the plate A of the cam N T 5 and its toothed-segment dwith the plate B, its G ION JONLS' spindle f, carrying the worm M and worln- Witnesses: wheelg, and. the spindle z and worm h, all sub- HARRY L. ASHENFELTER,

stantially as described. HARRY SMITH. 

